1. Field of the Invention
The invention relates to the field of processing large rolls of sheet material. More particularly, the invention relates to cutting such large rolls. More particularly yet, the invention relates to sub-dividing an industrial-size roll of sheet material into two or more individual rolls.
2. Description of the Prior Art
Paper for the printing industry is provided on rolls of various widths. Often, it is necessary to re-size a roll from its original state, that is, to reduce the width of the roll, or to cut an end from a roll of paper that has been damaged. The conventional method of re-sizing such a roll is to run the paper through a rewinder. This process entails feeding the paper through a slitter that cuts the paper to the desired width with a blade, and rewinding the slit or cut material onto one or more rolls, as applicable. One of the largest industrial-size rolls of paper has a diameter of 72 inches and a paper width of 138 inches. Rolls this large are typically not re-sized on a rewinder, because the rewinder equipment for handling such large rolls would be extremely costly and space-consuming. Also, the rolls that require re-sizing are often not at a facility that has a rewinder. Because such rolls are extremely large, heavy, and difficult to handle and to transport, it is very costly and time-consuming to ship them to a facility that does have a rewinder. Thus, the rolls are generally re-sized on location, by cutting the rolls with a chain saw to the approximate size and then finishing the ends of the cut rolls in a finish or trim process. Because of the complexity and large number of components that are need in rewinding equipment, it is not feasible to construct a rewinder that is a mobile unit.
Special roll-cutting machinery is used to cut and re-finish industrial-size paper rolls. In U.S. Pat. No. 6,269,719 B1, Easton et al. discloses machinery that is used to cut a roll into a narrower roll. The Easton et al. machinery provides a horizontal bed that supports a roll of paper and a rotary arm unit that includes a circular saw. The saw is mounted in such a way that it can be positioned along the roll only a few inches in from the end of the roll. Furthermore, the radius of the saw blade is small, typically with a 10-inch radius and, thus, much smaller than the radius of an industrial-size roll. In order for the saw to be able to cut across the cutting plane in toward the center of the roll, the material that has been cut must be removed rather quickly from the roll. To facilitate removal of this material, radial slices are cut into the end of the roll with a chain saw or a handheld circular saw to the approximate depth of the desired cut before the cut is made. As the saw cuts in from the outer perimeter, strips of the trimmed waste paper drop off or are pulled off and are discarded as waste paper and/or recycled.
U.S. Pat. No. 5,964,024 (Wallace; 1999) discloses apparatus that includes a roll cutter that is similar in purpose to that of the Easton et al. roll-cutting machine, but with the roll of paper supported in a vertical position on a rotating base. As with the Easton et al. machinery, the saw is small, relative to the diameter of the roll to be cut. A second, hand-operated circular saw may be used to cut radial cuts into the end of the roll to a depth of the desired trim cut, so that the paper may be quickly removed as the saw travels inward toward the core. In this case, because the roll is supported vertically, spacers are inserted into the cut as the saw moves in toward the core, to prevent the upper part of the roll from slipping down and binding the saw. And again, if a wide roll of paper is to be divided into two or more rolls, a chain saw is used to first cut through the original roll at the approximate locations of the desired cut or cuts and the ends of each roll are then trimmed in separate operations.
Both the Easton et al. and Wallace equipment are provided as mobile units. That is, the roll-cutting machinery is mounted on a transport vehicle and brought to the location of the rolls that are to be cut. Thus, the facility that processes such rolls collects and stores the rolls and, at intervals, calls upon the roll-cutting service. This, of course, requires space, roll-handling equipment, and administrative effort to store and keep track of the rolls, in order to determine when it is economically feasible to hire the roll-cutting service to come with the roll-cutting machinery and cut the rolls.
The conventional roll-cutting machinery and methods of cutting, whether the rewinder operation or the cutting operations described above, have disadvantages that make it a difficult or costly process to reduce the width of a roll. The rewinder method requires sophisticated equipment that makes this method not practicable as a mobile unit, so that the owner that processes such large industrial size rolls must either have the rewinder equipment permanently installed to slit, or must ship the rolls to a location that provides that service. This, again, is very costly because of the transportation costs. Furthermore, it is critical that the rewinding be done properly, as improperly wound paper can dramatically change the physics of the originally manufactured roll, making it unusable for its intended purposes.
It is known in other industries to use a large circular saw blade to cut through a large cylindrical form of material. Saw blades used in the lumber industry come to mind. None of the known blades is capable of cutting through a large, industrial-size roll of paper in a single-cut operation, leaving one or more rolls with smooth, finished, press-ready ends that require no further trimming or other operations to prepare them for subsequent processing.
What is needed, therefore, is machinery that efficiently cuts rolls in a single-cut operation and leaves a press-ready roll with a smooth, finished roll end that requires no further trimming or other end-finishing operations. What is further needed is such machinery that is capable of sub-dividing a roll into narrower rolls, with little or no waste. What is yet further needed is such machinery that accepts rolls in a wide range of widths and is adaptable to cut through a roll at virtually any location along the width of the roll.